Two of the most powerful men in United States history are heartbroken over the death of Franco Harris ... with both Joe Biden and Barack Obama saying Wednesday they're devastated by the Steelers legend's passing.
The current POTUS and the ex-POTUS both took to their social media pages to remember the Pro Football Hall of Famer ... with Biden explaining he'd actually been a friend of Harris' for years.
"I knew him for his character and compassion," Biden said, "someone who spent time with my boys after we lost my first wife and infant daughter.